The purpose of this project is (1) to see whether sleep apnea with hypoxia and sleep interruption affect insulin secretion and whether this is an independent effect or modulated by GH, cortisol, glucagon, or catecholamines; (2)to determine whether patients on long-term treatment (>5 mos) have changes in the insulin axis when treatment is abruptly discontinued; and (3) to determine if insulin secretion in these patients is comparable to that observed in controls matched for age, weight, anthrompomorphic measures, and blood pressure.